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Berlin, 17-06-2016 BONE CONDUCTION BOA WHY AND WHEN? Kristin Kerkhofs Audiologist & Lecturer Berlin, 17-06-2016 BOA? • Behavioural Observation Audiometry “Observation of an unconditioned response to acoustic stimuli at the age of 0-6 months” • Behavioural observation ? Berlin, 17-06-2016 Paediatric Audiology Team - Flanders , Belgium since 2001 Bruges Ostend Ghent Deinze Courtrai Antwerp Hasselt Brussels Berlin, 17-06-2016 Our mother of pediatric audiology… Marion Downs 1914-2014 Berlin, 17-06-2016 Monique Delaroche (Bordeaux) Rehabilitation centre 1992 I 1998 I 2002 I UEHS Kind & Gezin (Child & Family) 2016 I Berlin, 17-06-2016 SCREENING IN FLANDERS (northern part of Belgium) by Kind & Gezin (Child and Family) • Community based UEHS since 1998 • Screening by a K&G nurse under the age of 4 weeks (at home or at the regional house) • 2 steps protocol: AABR/AABR until 2013 – since 2013 SSEP/SSEP • Referral to specialised center for audiological/medical assessment, early home guidance, rehabilitation • Since 1998 : 1 072 586 screened newborns • Target cover: >98% Berlin, 17-06-2016 Audiological assessment after screening OBJECTIVE HF Tympanometry Otoacoustic Emissions (TEOAE or DPOAE) ABR and ASSR SUBJECTIVE Behavioral Observation Audiometry (BOA) Bone conduction Insert earphones Berlin, 17-06-2016 Berlin, 17-06-2016 Why Behavioural Observation Audiometry? • Cross-check principle: ‘The cross-check Principle in Pediatric Audiometry’. 1976 J.F. Jerger & D. Hayes (Archives of Otolaryngology) • Special cases: ANSD • In deaf children responses can be measured at a high level when performed at a very young age Berlin, 17-06-2016 Why BOA with bone conduction? • Response of the best inner ear • More reactive responses • Presence air-bone gap • Prevalence of middle ear problems such as OME • Special cases • ANSD • Unexpected permanent conductive hearing loss (example: incudostapedial disconnection) Berlin, 17-06-2016 Prevalence of Temporary Conductive HL Berlin, 17-06-2016 Purpose of BOA • BOA’s purpose is to obtain air and bone conduction data as close as possible to the hearing threshold for a broader frequency range of at least 500 - 4000 Hz. • This can only be performed in optimal test conditions and by following a strict protocol and has to be done by experienced pediatric audiologists (preferably with 2 audiologists) • Best age: before 3 months Berlin, 17-06-2016 Setup Optimal test conditions • light sleep • during feeding or while sucking • check whether the child is in a deep sleep! Transducers • BC: diadem or softband with vibrator (different sizes!) • AC: insert earphones with foamtip or earmold Stimulus • Warble or Freshnoise Berlin, 17-06-2016 Procedure • To obtain the minimal response level of the child it is necessary to start below the expected threshold. A proper reaction can only be obtained when reaching the minimal response level for the first time for each frequency. • Start with bone conduction at 30dBHL • Continue with air conduction (insert earphones) and use the measured threshold from BC or use information from ABR • Minimize cue signals • Increasing stimulus level • Variate stimuli & ear Berlin, 17-06-2016 Response behavior • • • • • • • • • opening eyes moving eyelashes eye widening frowning start or stop sucking eye blink decreased motion increased motion … ! The number of observable responses is limited Berlin, 17-06-2016 Minimal response level (MRL) with Behavioral Observation Audiometry (BOA)? Our findings in … • normal hearing babies • hearing impaired babies mild-moderate severe-profound Berlin, 17-06-2016 MRL with bone conduction obtained through BOA with normal hearing babies aged 4 to 8 weeks (after AABR-PASS) [De Poolster, 2004] Berlin, 17-06-2016 MRL with insert phones obtained through BOA with normal hearing babies aged 4 to 8 weeks (after AABR-PASS) [De Poolster, 2004] Berlin, 17-06-2016 MRL in hearing impaired babies? - Mild to moderate hearing loss - Severe to profound hearing loss • Monique Delaroche “Is behavioral audiometry achievable in infants younger than 6 months of age?” (2011) • Jane Madell "Pediatric Audiology“ (2008) • future study Berlin, 17-06-2016 Example of similarity between the MRL obtained through BOA, VRA and CPA of a hearing impaired infant (De Poolster) 1. BOA 3m 2. VRA 7m 3. CPA 2jr 1 2 3 2 3 1 3 1 2 Berlin, 17-06-2016 Video BC BOA Berlin, 17-06-2016 Case 1: temporary conductive HL BOA at age of 2 weeks • HF TYMP abnormale • OAE absent BOA at age of 4 weeks • HF TYMP = normale • OAE present Berlin, 17-06-2016 Case 2: mild hearing loss BOA 2m • • • VRA 6m TYMP: normal OAE: absent ABR: 50dBnHL Berlin, 17-06-2016 Case 3: ANSD (auditory neuropathy spectrum disorder) BOA at the age of 2 month TYMP: normal OAE: present ABR: no response Berlin, 17-06-2016 BONE CONDUCTION BOA WHY? TYMP ABR OAE SSEP BOA is an essential part of the puzzle... Berlin, 17-06-2016 But... • can only be performed by experienced pediatric audiologists • is a time consuming examination • demands a lot of patience! (from examiner and parents) Berlin, 17-06-2016 BONE CONDUCTION BOA WHEN? ALWAYS! Berlin, 17-06-2016 More information? www.biap.org Berlin, 17-06-2016 Thanks for your attention!